New 89

Hey dlvfsh9 here, recently purchased an 89 project. Have a few problems and wondering if anyone has any advice. I made it about 1/4 mile from the purchase point and she stopped running. waited a few minutes and started her again, ran about 35 seconds and did the same thing (tried 3 times and gave up). Towed her home, she started right up, ran fine and parked it. The expansion tank leaks as soon as she gets warm (ordered a new one). Has any one experienced any of the same symptoms? Any advice is much appreciated.

I'm still learning a lot of this too so bear with me... but sounds to me like its overheating and after waiting its cooling down enough that you can restart it... maybe air in the cooling system?

The two symptoms are not likely related.

A common cause of "stalling" on the 4.0 is a flaky crankshaft position sensor. Without that input signal going to the computer, the engine will NOT have spark and it will NOT have fuel going to the fuel injectors.

Thermal failure of the crank sensor (heat related) is not uncommon.

Here is a thread that gets into this sensor further.....

http://www.naxja.org/forum/showthread.php?t=1044073

Hey guys thanks for the advice. I think i will check into the crankshaft position sensor for the stalling issue, and the air in the cooling system when i replace the expansion tank. Will let you know how it goes.

Purchase a Stant 10244 pressure cap for your bottle. It is off a Volvo pressure bottle from a 740 series 2.3L engine. It will seal, it has a higher than stock psi rating--raises your coolant's boiling point, and it has a lower profile so it won't be impacting the underside of the hood when the bottle expands. Don't overfill the pressure bottle, fill it no more than 1/4 to 1/3 full when cold.

I'm with birchlakeXJ, start with testing the crank sensor, it should have 200 ohms of resistance + or - 75 ohms (125-275 ohms). They are subject to thermal failure, so it might test Ok cold but cut out when warmed up. The ICM/coil will do this too.

Grounds are ABSOLUTELY ESSENTIAL on the Renix XJs. Start with the heat-to-firewall braided strap. It is a POS waiting to bite you in the A**. Replace it with a 4 or 2 gauge cable. Strip the metal bare, treat with an anti-corrosive agent (any hardware/paint store) and make the connections TIGHT. Next, the dipstick has CRITICAL grounds on it. ECU, ICM/coil, o2 sensor, and others. Strip to bare metal, anti-corrosive, make them TIGHT.

Article on improving the Renix electrical system: http://www.olypen.com/craigh/charge.htm

Check your fuse block, under the dash, driver's left foot. The clutch MC will leak and the fluid will corrode the fuse block. Also, based on age, you should pull all of the fuses and clean the contacts in the fuse block--they get real nasty over the years.

Sounds kinda like a flaky fuel pump ballast resistor to me, or maybe a bad fuel pump... could be a number of other things as well.

Ok so i got the new feuel pump. It does not look exactly like the old one. Has any body had to modify the top mounting plate to make a replacement pump fit or did i get the wrong one?

You jumped straight to replacing the fuel pump? Did you checked (or bypassed) the ballast resistor and the CPS first?

Make sure you read all the replys and dont jump to the simple conclusions. Joe Peters, I wish you would have posted that 6 months ago!! That post and link is the sh*t!!! Now I can finally take the last steps to hopefully fixing that annoying electrical problem!!! Something so simple but causes so many problems!!! Thanks a lot

Ok lawsoncl i might have jumped the gun a little, but i still haven't put the new pump in yet. What is the process to check or bypass the ballast resistor and CPS? As to Joe's post duly noted.

dvlfsh9 said:

Ok lawsoncl i might have jumped the gun a little, but i still haven't put the new pump in yet. What is the process to check or bypass the ballast resistor and CPS? As to Joe's post duly noted.

Click to expand...

BirchLakeXJ already posted a good link with info on testing the CPS sensor. http://www.naxja.org/forum/showthread.php?t=1044073. Basically, measure it's resistance with a meter. In particular measure it when its misbehaving.

The ballast resistor is the whitish ceramic thing on the drivers fender with a wire plugged into either end. The power for the fuel pump goes through this resistor when the key is in the run position. It gets bypassed when cranking, so if it's cracked or poor connections you get the symptoms of the fuel pump not running after you stop cranking and the engine dies. Jumper the two wires together and see if it runs better. You can leave it this way permanently as the later models don't have this at all.

NewBreedCustom said:

Make sure you read all the replys

Click to expand...

Also, do you have the infamous C101 connector shown here? http://www.jeepforum.com/forum/f11/c101-connector-renix-disassembly-1079829/

lawsoncl thanks for the info. I'm going to do some exploratory work this morning and i should have a post this after noon about my findings. Have a great Sunday.

The good news, No infamous C101 connector. Does this mean that my 89 was manufactured later in that year?

dvlfsh9 said:

The good news, No infamous C101 connector. Does this mean that my 89 was manufactured later in that year?

Click to expand...

I believe that is correct. I know my 89 MJ was manf later in the year since it had the ax15 transmission and it does not have the C101 connector either.